Reply With Quotethanks for that gtirx2 think i will stick with this turbo instead of changing it, just signed up to the temp tc
I think you know my thoughts on your turbo already but its still interesting to see what everyone else thinks.
I had been researching my ihi hybrid a while back and was trying to make sence of it all,and still never got completely to the bottom of the exhaust housings between the uno and punto.
Just from what I have read in various places and guesstimates I will put a short version of how I think it is lol,I could be completely wrong but I am always interested to learn about the ihi hybrids and am by no means an expert.
I think both uno and punto use the same size exhaust wheels be it vl2/3,vl5 or vl7,I think the exhaust wheel inducer size on these wheels is 52.5mm.
Exducer size I am usure of and there is a possibility that there are very small differences between the 3 but as mention above I think they are the same,if there is a difference I think it will be very minimal indeed.
Comp wheels,still not 100% on these but all vl2/3,vl5 and vl7 use a 52.5mm exducer comp wheel.
The difference in the comp wheels is inducer size,just from memory and from what I have read I think its something like 32mm for the vl2/3,34mm vl7 and 35mm vl5,as mentioned I am not totally sure here.
Then there is the slight unknown to the exhaust housings between the mk1 uno and puntos,I am not sure if they are both classed as ihi 7r housings like the mk1 unos is.
It was pointed out to me that I somehow completely overlooked lol is the inlet shape and size is different between the 2,and the punto is the better flowing of the 2 with the t2 flange.
If they are both still considered around the same sort of ar (ihi 7r) size I am unsure of,the flange size all plays a part in this ar size aswell and as mentioned the punto is better but how much better I don’t know.
I think 10bhp was mentioned but I don’t think there would be a massive improvement ,and by the spool up times and similar wheel sizes I would say that the exhaust housing are also pretty similar in power output.
Then to the turbo dynamics hybrids,as far as I can make out all the off the shelf uno or punto hybrids use the stock exhaust wheel.
The only change(other than bearing and oil hole changes) on stage 2 and up turbos is the exhaust wheel has cut back blades.
Which as far as I can make out has a similar effect as to what running a slightly larger exhaust housing would give you,less back pressure-less heat,better flow but at the expense of a bit of spool for more top end.
How much this can really gain just from a cut back I don’t know,but if you look at the stage 1 punto md57 and md103 the only real or important difference is the cut back blades
This is proberly why the md57 is only recommend to run up to 15psi as running much more will proberly just produce more heat due to the higher back pressure ?
Where as the md103 can produce more power due to the better flowing exhaust side and less back pressure and in turn run more boost?
Then the uprated comp wheels, as far as I can make out the stage 1 uno and stage 1 and 2 punto all use the same wheel,this wheel I believe is an ihi vj20 wheel.
This wheel has the same size 52.5mm exducer as the stock turbos but with a much larger 39.11mm inducer.
My turbo the stage 2 md97 once again has the same size exducer but with a slightly bigger 40.16mm inducer,I think this wheel is an ihi vj22 wheel.
I am usure on exducer sizes of the larger wheeled hybrids,but at a guess I would say the stage 3 is still the same but the punto stage4/uno stage3 may have a larger exducer going by the inducer size?
Anyhow heres a pic of my turbo for comparison and to add abit of scale,remembering my turbo has a 1mm larger wheel than a md103.
So going by the pics and abit of a guess I think st17 turbo proberly has the stage4 md143 42.25mm inducer comp wheel.
But then you need to consider his turbo is also running what looks to be a much larger exhaust wheel than any of these hybrids and inturn will help the exhaust side flow a lot better at the expense of some spool.
I still think the main thing that will proberly hold it back abit though is the exhaust housing, but as above the larger exhaust wheel will no dout improve its flow and what power it can make.
Imo and going by the pics it is most likely a 200bhp+ turbo and more than likely custom made by turbo dynamics and was not off the shelf.
Like I say I can only go from what I have read and may be way off with my thinking lol and there are proberly a few other variables I have missed but I think the above is sort of correct?
I think it basicly comes down to what the comp wheel can flow and how efficiently the exhaust side is at powering it.
For an example when I was looking into gtir turbos you can have either a t2 .64ar gt2871r or a t2 .64ar gt3071r both can be speced to use the exact same comp wheel so the only real difference is the exhaust wheels.
The gt28 with the smaller wheel cant quite power the comp wheel to its full potensal but has good spool with a max power output with the smaller .64 housing is around 380bhp,the gt30 with its bigger better flowing exhaust wheel in the same housing will make closer to 450bhp.
Both turbos can suffer boost creep though in the smaller housing and people also have backpressure concerns but I surpose that’s the price you pay for good spool.
You can move up to the larger .86 housing and have less backpressure, no creep and proberly 20bhp more on both but at the expense of proberly 500rpm spool and maybe worse transient response.
Like I say there are a lot of variables and I don’t understand it all tbh but the above is how I see it atm lol
Anyhow here is the punto and uno hybrid specs…
Punto
MD57 High flow 3911 Trim Compressor wheel, C.N.C. re-profiled compressor housing, 360 degree thrust bearing, left hand thread shaft & wheel assembly. Uprated actuator –optional. Recommended maximum boost level is 14 - 15 P.S.I.
MD103 High flow 3911 Trim Compressor wheel, C.N.C. re-profiled compressor housing, modified inlet throat, 360 degree ramped thrust bearing, left hand thread shaft & wheel assembly with cut back turbine blades, large hole bearing housing, Uprated actuator - optional. Recommended maximum boost level is 20 - 22 P.S.I.
Output Achieved - 198 Bhp & 340 Ftlbs Torque
MD143 High flow 4225 Trim Compressor wheel, C.N.C. re-profiled compressor housing, 360 degree thrust bearing, left hand thread shaft & wheel assembly with cut back turbine blades, large hole bearing housing. Uprated actuator –optional. Recommended maximum boost level is 22 - 24 P.S.I.
MD367 High flow 4726 Trim Compressor wheel, C.N.C. re-profiled compressor housing, 360 degree thrust bearing, left hand thread shaft & wheel assembly with cut back turbine blades, large hole bearing housing. Uprated actuator –optional. Recommended maximum boost level is 22 - 24 P.S.I. Note: Drag Racing use only.
Uno
MD18 High flow 39.11mm inducer compressor wheel, C.N.C. re-profiled compressor housing, 360 degree thrust bearing, left hand thread shaft & wheel assembly. Uprated actuator –optional. Recommended maximum boost level is 14 - 15 P.S.I.
MD97 High flow 40.16mm inducer compressor wheel, C.N.C. re-profiled compressor housing, modified inlet throat, 360 degree ramped thrust bearing, left hand thread shaft & wheel assembly with cut back turbine blades, large hole bearing housing, Uprated actuator - optional. Recommended maximum boost level is 18 – 20 P.S.I.
MD115 High flow 42.25mm inducer compressor wheel, C.N.C. re-profiled compressor housing, modified inlet throat, 360 degree ramped thrust bearing, left hand thread shaft & wheel assembly with cut back turbine blades, large hole modified bearing housing, Uprated actuator - optional. Recommended maximum boost level is 22 – 25 P.S.I.
Oh and st17 there is a temp uno turbo site up and running while tc is down if you have not seen it…
http://fiatunoturboowners.forumotion.co.uk/
thanks for that gtirx2 think i will stick with this turbo instead of changing it, just signed up to the temp tc
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